It is rare to have touch issues across two different screens and it be related to a bad part. You can try another part from a different supplier as the first one just to cross check and ensure that the issue is not screen related. If the issue continues with another screen, the issue is related to either the display connector on the logic board, components near the display connector damaged, or separation between the two layers of the board which commonly happens from a heavy drop or impact. These are all fixable by a board repair technician.